Self expanding electrode cuff

ABSTRACT

An expandable electrode cuff includes a first flange member, a second flange member, and a third flange member, which together provide a variable-sized lumen about a nerve.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of U.S. patentapplication Ser. No. 12/114,352, entitled SELF EXPANDING ELECTRODE CUFF,filed May 2, 2008, which is incorporated herein by reference

TECHNICAL FIELD

The invention relates generally to an implantable stimulation system forstimulating and monitoring soft tissue in a patient, and moreparticularly, the invention relates to an expandable electrode cuff forpositioning an electrode of an implantable stimulation system about anerve for stimulation and/or monitoring of nerve tissue.

BACKGROUND

Sleep apnea generally refers to the cessation of breathing during sleep.One type of sleep apnea, referred to as obstructive sleep apnea (OSA),is characterized by repetitive pauses in breathing during sleep due tothe obstruction and/or collapse of the upper airway, and is usuallyaccompanied by a reduction in blood oxygenation saturation.

One treatment for obstructive sleep apnea has included the delivery ofelectrical stimulation to the hypoglossal nerve, located in the neckregion under the chin. Such stimulation therapy activates the upperairway muscles to maintain upper airway patency. In treatment of sleepapnea, increased respiratory effort resulting from the difficulty inbreathing through an obstructed airway is avoided by synchronizedstimulation of an upper airway muscle or muscle group that holds theairway open during the inspiratory phase of breathing. For example, thegenioglossus muscle is stimulated during treatment of sleep apnea by acuff electrode place around the hypoglossal nerve.

Because of the significant amount of movement in multiple directionsthat can take place under the chin, positioning an electrode to enablestimulation of the hypoglossal nerve becomes a significant challenge. Onthe one hand, placement of the electrode and lead in close proximity tothe hypoglossal nerve can result in irritation to the nerve as a resultof normal motion of the chin and neck, while on the other hand, withoutclose adherence to the nerve, buildup of connective tissue between thenerve and the electrode and lead can occur, causing low thresholds,thereby reducing the effectiveness of the delivered stimulation by thedevice.

Another challenge in placing an electrode for nerve stimulation therapyrelates to the tendency of the hypoglossal nerve to swell, which canresult in the nerve being strangled by the electrode and lead. Inaddition, once the electrode cuff has initially been implanted, fibrosistends to cause the location of the electrode cuff to become more fixed.Therefore, the first month post implant is critical to keep theelectrode cuff properly positioned on the nerve, while at the same timeit is important not to “suffocate” a swelling nerve. An additionalchallenge in placing the electrode for nerve stimulation results fromthe fact that stimulation currents need to be confined to thehypoglossal nerve in order to prevent other nearby nerves or musclesfrom being stimulated, which results in patient discomfort and loss ofsleep. Therefore, what is needed is an improved electrode cuff thatenables positioning of an electrode about a nerve.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects and features of the present invention will be appreciated as thesame becomes better understood by reference to the following detaileddescription of the embodiments of the invention when considered inconnection with the accompanying drawings, wherein:

FIG. 1 is a schematic diagram of an implantable stimulation system thatincludes a self-expanding nerve cuff according to an embodiment of theinvention;

FIG. 2 is a side view of a lead utilized in an implantable stimulationsystem according to an embodiment of the invention;

FIG. 3 is a front view of an expandable electrode cuff according to anembodiment of the invention;

FIG. 4 is a front view of the expandable cuff of FIG. 3 in anintermediate open position according to an embodiment of the invention;

FIG. 5 is a front view of the expandable electrode cuff of FIG. 3 in afully open position according to an embodiment of the invention;

FIG. 6 is a schematic diagram illustrating positioning of an expandableelectrode cuff over a desired nerve according to an embodiment of theinvention;

FIG. 7 is a front view of an expandable electrode cuff positioned abouta nerve in an intermediate open position according to an embodiment;

FIG. 8 is a front view of an expandable electrode cuff positioned abouta nerve in a fully engaged position according to an embodiment;

FIG. 9 is a front view of an expandable electrode cuff positioned arounda nerve according to an embodiment of the invention;

FIG. 10 is a front view of an expandable electrode cuff according to anembodiment of the invention;

FIG. 11 is a front view of the expandable cuff of FIG. 10 in anintermediate open position according to an embodiment of the invention;

FIG. 12 is a front view of the expandable electrode cuff of FIG. 10 in afully open position according to an embodiment of the invention;

FIG. 13 is a front view of an expandable electrode cuff positioned abouta nerve in an intermediate open position according to an embodiment;

FIG. 14 is a front view of an expandable electrode cuff positioned abouta nerve in a fully engaged position according to an embodiment;

FIG. 15 is a front view of an expandable electrode cuff positionedaround a nerve according to an embodiment of the invention;

FIG. 16 is a top view of an expandable electrode cuff according to anembodiment of the invention in the fully open position;

FIG. 17 is a top view of an expandable electrode cuff according to anembodiment of the invention in the fully open position;

FIG. 18 is a top view of an expandable electrode cuff according to anembodiment of the invention in the fully open position; and

FIGS. 19-21 are front views of an expandable electrode cuff according toembodiments of the invention.

DESCRIPTION OF EMBODIMENTS

The following detailed description is merely exemplary in nature and isnot intended to limit the invention or the application and uses of theinvention. Furthermore, there is no intention to be bound by anyexpressed or implied theory presented in the preceding technical field,background, brief summary or the following detailed description.

FIG. 1 is a schematic diagram of an implantable stimulation system thatincludes a self-expanding nerve cuff according to an embodiment of theinvention. As illustrated in FIG. 1, an example of an implantablestimulation system according to one embodiment of the invention includesan implantable pulse generator (IPG) 55, capable of being surgicallypositioned within a pectoral region of a patient 10, and a stimulationlead 52 electrically coupled with the IPG 55 via a connector (not shown)positioned within a connection port of the IPG 55. The lead 52 includesan electrode or electrode system 65 and extends from the IPG 55 so thatthe electrode system 65 is position around a desired nerve, such as thehypoglossal nerve 53 of the patient 10, to enable stimulation of thenerve 53, as described below in detail. An exemplary implantablestimulation system in which lead 52 may be utilized, for example, isdescribed in U.S. Pat. No. 6,572,543 to Christopherson et al.,incorporated herein by reference in its entirety, and further includes asensor lead 57 electrically coupled to the IPG 55 and extending from theIPG 55 so that a sensor or transducer 60 can be positioned in thepatient 10 for sensing of respiratory effort.

The sensor 60 may be a pressure sensor that is surgically implanted in aregion that has pressure continuity with the intrapleural space, such asthe suprasternal notch, the space between the trachea and esophagus, orby being attached to either of the trachea or esophagus. The sensor 60may also be positioned intercostally, or secured in a position forsensing pressure at the posterior side of the manubrium. Thesuprasternal notch 62 and manubrium 63 of the sternum 64 are well knownstructures on the upper chest that are in anatomical continuity with theintrapleural space. It is also well known that changes in intrapleuralpressure provide a characteristic respiratory effort waveform.

The location for placement of the sensor 60 is, at least in part, chosenas a function of a delay, i.e. the propagation time associated with apressure waveform characteristic of respiratory effort propagating fromthe respiratory point of origin to the sensor position. The chosenlocation is also a function of the amount of filtering necessary toachieve a usable sensed signal at a particular location, i.e. the amountof filtering that is necessary to remove waveforms other than thewaveform associated with the desired sensed characteristic, such as thefiltering required to remove cardiac waveform activity, for example. Thepositioning of the sensor 60 enables the IPG 55 to receive respiratoryeffort waveform information utilized to determine increased respiratoryeffort, which is then used by the IPG 55 to control delivery of therapyin response to determined increases in respiratory effort.

FIG. 2 is a side view of a lead utilized in an implantable stimulationsystem according to an embodiment of the invention. As illustrated inFIG. 2, a lead 100 according to one embodiment includes a lead body 102extending from a proximal end 104 to a distal end 106, with a connector108 positioned at the proximal end 104 for electrically connecting thelead 100 to the IPG 55. An expandable electrode cuff 110, positioned atthe distal end 106 of the lead body 102, is capable of being positionedaround a nerve, such as a hypoglossal nerve for example, in order tostrategically locate one or more electrodes 112 embedded within theelectrode cuff 110 so as to be adjacent to the nerve when the electrodecuff 110 is positioned around the nerve. Conductors (not shown) arepositioned within the lead body 102 to electrically connect theelectrodes 112 and the connector 108 so that the electrodes 112 areelectrically coupled to the IPG 55 via respective connector pins 114 ofthe connector 108, as is known in the art.

FIG. 3 is a front view of an expandable electrode cuff according to anembodiment of the invention. As illustrated in FIG. 3, according to oneembodiment, the expandable electrode cuff 110 is a single, unitarymolded piece that includes a base portion 120 having a top wall 122 anda bottom wall 124 extending from a first side wall 126 to a second sidewall 128. A first flange member 130 extends from a proximal end 131 to adistal end 312, and is located at the top wall 122 of the base portion120 to extend from the first side wall 126 to the distal end 132. Asecond flange member 134 extends from a proximal end 135, and is locatedat the top wall 122 of the base portion 120 to extend from the secondside wall 128 to the distal end 136. As will be described below, theelectrode cuff 110 is expandable both during implantation of the lead100 and electrode cuff 110, and after the electrode cuff 110 ispositioned around a desired nerve for delivery of electrical stimulationtherapy to the nerve.

During it's normal, unbiased state, prior to insertion around the nerve,the electrode cuff 110 is in a fully engaged position, shown in FIG. 3,in which the distal end 132 of the first flange member 130 is positionedadjacent to and may engage against the second side wall 128 at alocation below the proximal end 135 of the second flange member 134 andbelow the top wall 122 of the base portion 120, and the distal end 136of the second flange member 134 is positioned at a location above theproximal end 131 of the first flange member 130 and above the top wall122 of the base portion 120 along the first side wall 126.

The first flange member 130 has a length greater than the second flangemember 134 so that when the electrode cuff 110 is in the fully engagedposition, the first flange member 130 and the second flange member 134form a lumen 140 for receiving a nerve therein, with an inner side wall141 of the second flange member 134 forming an inner wall 142 of thelumen 140 so as to position the electrodes 112 (shown in FIG. 2), whichare embedded within the second flange member 134, adjacent to the nerve(not shown in FIG. 3).

In addition, when the electrode cuff 110 is in the fully engagedposition, an inner side wall 144 of the first flange member 130 ispositioned over and engages against an outer side wall 146 of the secondflange member 134, and therefore an outer wall 148 of the first flangemember 130 forms an outer wall 143 of the lumen 140. In this way, whenthe electrode cuff 110 is in the fully engaged position shown in FIG. 3,both the first flange member 130 and the second flange member 134 extendover the base portion 120, the first flange member 130 forms an outerportion of the electrode cuff 110, and the second flange member 134forms an inner portion of the electrode cuff 110 for engaging the nerve.Depending on the size of the nerve, once positioned about a nerve, theelectrode cuff 110 may be in either the fully engaged position of FIG. 3or in a partially fully engaged position, wherein the distal end 132 ofthe first flange member 130 may be spaced from rather than engagedagainst the second side wall 128, and the distal end 136 of the secondflange member 134 may be spaced from rather than aligned with the firstside wall 126 at the top wall 122 of the base portion 120, as will bedescribed below.

FIG. 4 is a front view of the expandable cuff of FIG. 3 in anintermediate open position according to an embodiment of the invention.As illustrated in FIG. 4, during positioning of the electrode cuff 110over the desired nerve so that the nerve can be properly located withinthe lumen 140, the electrode cuff 110 is advanced from the fully engagedposition shown in FIG. 3, to an intermediate position shown in FIG. 4,in which the distal end 132 of the first flange member 130 is advancedaway from the second side wall 128, and the inner side wall 144 of thefirst flange member 130 is advanced away from the outer side wall 146 ofthe second flange member 134 so that the distal end 132 extends outwardfrom and along the first side wall 126 of the base portion 120. As aresult, when the electrode cuff 110 is in the intermediate openposition, the first flange member 130 is not positioned so as to extendover the top wall 122 of the base portion 120, and the distal end 132 isno longer positioned below the top wall 122 of the base portion 120,while the second flange member 134 remains positioned to extend over thetop wall 122 of the base portion 120 with the distal end 136 of thesecond flange member 134 positioned above the proximal end 131 of thefirst flange member 130. In addition, the inner side wall 144 of thefirst flange member 130 is no longer positioned over and adjacent to theouter side wall of 146 of the second flange member 134 when the cuff 110is in the intermediate open position of FIG. 4.

FIG. 5 is a front view of the expandable electrode cuff of FIG. 3 in afully open position according to an embodiment of the invention. Asillustrated in FIG. 5, once the electrode cuff 110 is in theintermediate open position, the distal end 136 of the second flangemember 134 is advanced away from the top wall 122 of the base portion120 and the first side wall 126 so that rather than being positionedabove the proximal end 131 of the first flange member 130, the distalend 136 of the second flange member 134 extends outward from the secondside wall 128 so that the second flange member 134 does not extend overthe second side wall 128 of the base portion 120, resulting in the innerwall 142 of the second flange member 134 no longer forming the lumen 140when the cuff is in the fully open position of FIG. 5. As a result, whenthe electrode cuff 110 is in the fully open position, neither the firstflange member 130 nor the second flange member 134 are positioned so asto extend over or near the top wall 122 of the base portion 120 of theelectrode cuff 110, the inner side wall 144 of the first flange member130 is no longer positioned over or near an outer side wall 146 of thesecond flange member 134, and the inner side wall 141 of the secondflange member 134 no longer forms the inner wall 142 of the lumen 140.In this way, by enabling the electrode cuff 110 to be advanced betweenthe fully engaged position, the intermediate open position, and thefully open position, the invention enables the cuff 110 to be moreeasily positioned over a nerve during implantation of the lead 100, asdescribed below.

FIG. 6 is a schematic diagram illustrating positioning of an expandableelectrode cuff over a desired nerve according to an embodiment of theinvention. As illustrated in FIG. 6, during the initial positioning ofthe lead and positioning of the electrode cuff 110 over a nerve, such asover a hypoglossal nerve 200, once the nerve 200 has been dissected outover a desired range, such as over 1-3 cm range, for example, theelectrode cuff 110 is advanced from the normal, fully engaged positionof FIG. 3 to the fully open position of FIG. 5 so that the inner flange134 of the electrode cuff 110 is then inserted under the nerve 200 whilein the fully open position, until the nerve 200 becomes positioned so asto be aligned with and against the top wall 122 of the base portion 120.

The inner flange member 134 is then released so that the inner flangemember 134 becomes positioned around the nerve 200. According to oneembodiment, prior to be advanced from the fully open position to theintermediate position, the base portion 120 of the electrode cuff 110 ispositioned inward, towards the body of the patient. As a result, oncepositioned under the nerve 200, the electrode cuff 110 is advanced fromthe fully open position to the intermediate open position (FIG. 4) sothat only the second flange member 134 is positioned over the top wall122 of the base portion 120, enclosing the nerve 200. The outer flangemember 130 is then released to be positioned around the nerve 200,resulting in the electrode cuff 110 being advanced from the intermediateopen position to a final engaged positioned (see FIG. 7), with both thefirst flange member 130 and the second flange member 134 beingpositioned over the top wall 122 of the base portion 120, enclosing thenerve 200 within the lumen 140 formed by the flange members 130 and 134.

FIG. 7 is a front view of an expandable electrode cuff positioned abouta nerve in an intermediate open position according to an embodiment. Asillustrated in FIG. 7, depending upon the circumference of the nerve200, once the nerve 200 is positioned over the top wall 122 of the baseportion 120 of the electrode cuff 110, and the inner flange member 134is positioned about the nerve 200 during the advancement of theelectrode cuff 110 from the fully open position of FIG. 5 to theintermediate open position of FIG. 7, the distal end 136 of the secondflange member 134 may be positioned to be spaced further above theproximal end 131 of the first flange member 130 and further away fromthe first side wall 126 and the top wall 122 of the base portion 120than when the electrode cuff 110 is in the intermediate open position ofFIG. 4. As a result, the size of the lumen 140 can be increased relativeto when the electrode cuff 110 is in the intermediate open position ofFIG. 4 to accommodate the size of the nerve 200.

FIG. 8 is a front view of an expandable electrode cuff positioned abouta nerve in a fully engaged position according to an embodiment.Similarly, during the advancement of the electrode cuff from theintermediate open position of FIG. 7 to the fully engaged positionduring implant of the electrode cuff 110, the distal end 132 of theouter flange member 130 may be positioned to be spaced further away fromthe second side wall 128 of the base portion 120 than when the electrodecuff 110 is in the fully engaged position of FIG. 3, and to be above,rather than below the proximal end 135 of the second flange member 134and the top wall 122 of the base portion 120, thereby increasing thesize of the lumen 140 relative to when the electrode cuff 110 is in thefully engaged position of FIG. 3 prior to be implanted to accommodatethe size of the nerve. Therefore, as illustrated in FIGS. 7 and 8, inorder to accommodate the size of the nerve, the first and second flanges130 and 134 can be advanced or expanded to increase the diameter of thelumen 140.

FIG. 9 is a front view of an expandable electrode cuff positioned arounda nerve according to an embodiment of the invention. If the smallarteries that run along the side of the nerve are overly restricted bythe electrode cuff 110, blood supply could be inhibited, causingtemporary or permanent damage to the nerve. The inventors have foundthat approximately 25 mmHg is the approximate amount of pressure thatmay be applied to the nerve without restricting blood flow. Asillustrated in FIG. 9, according to one embodiment, in order to addressthe effects of swelling of the hypoglossal nerve 200 that may sometimesoccur, particularly after the initial trauma associated with implantingthe electrode cuff 110, the first and second flange members 130 and 134are expandable so that the circumference of the lumen 140 formed by theelectrode cuff 110 is able to increase to accommodate increases in thediameter of the nerve 200 that occur subsequent to the initialpositioning of the expandable electrode cuff 110 about the nerve 200.For example, during swelling of the nerve 200 subsequent to implant ofthe device 100, the first flange member 130 and the second flange member134 expand so that the distal end 132 of the first flange member 130becomes positioned to be spaced further away from the second side wall128 of the base portion 120, and to be even further above, rather thanbelow the proximal end 135 of the second flange member 134 and the topwall 122 of the base portion 120. At the same time, the distal end 136of the second flange member 134 becomes positioned to be spaced furtherabove the proximal end 131 of the first flange member 130 and furtheraway from the first side wall 126 and the top wall 122 of the baseportion 120, thereby further increasing the size of the lumen 140 toaccommodate the swelling. As the swelling of the nerve 200 subsides, thefirst and second flange members 130 and 134 return towards the originalfully engaged position about the nerve 200 that occurred at the time ofimplant.

FIG. 10 is a front view of an expandable electrode cuff according to anembodiment of the invention. As illustrated in FIG. 10, according toanother embodiment, an expandable electrode cuff 310 includes a baseportion 320 having a top wall 322 and a bottom wall 324 extending from afirst side wall 326 to a second side wall 328, a first flange member330, a second flange member 334, and a third flange member 350. Thefirst flange member 330 is bonded at a proximal end 331 to the thirdflange member 350 along a portion of an outer wall 352 of the thirdflange member 350, and extends outward and over the top wall 322 of thebase portion 320 from the first side wall 326 to a distal end 332. Thesecond flange member 334 extends outward and over the top wall 322 ofthe base portion 320 from the second side wall 328 to a distal end 336.The third flange member 350 extends outward at the top wall 322 of thebase portion 320 from the first side wall 326 to a distal end 352.

In the expandable electrode cuff 310 of the embodiment of FIG. 10, thebase portion 320, second flange member 334 and the third flange member350 are formed from a single, unitary molded piece, with the firstflange member 330 bonded to the molded piece. As will be describedbelow, the electrode cuff 310 is expandable both during implantation ofthe lead 100 and electrode cuff 310, and after the electrode cuff 310 ispositioned around a desired nerve for delivery of electrical stimulationtherapy to the nerve, similar to the electrode cuff 110 described abovein the embodiment of FIGS. 3-5.

During it's normal, unbiased state, prior to insertion around the nerve,the electrode cuff 310 is in a fully engaged position, shown in FIG. 10,in which the first flange member 330 extends outward and over the topwall 322 of the base portion 320 from the first side wall 326 to thedistal end 332, the second flange member 334 extends outward and overthe top wall 322 of the base portion 320 from the second side wall 328to the distal end 336, and third flange member 350 extends outward atthe top wall 322 of the base portion 320 from the first side wall 326 tothe distal end 352 so that the third flange member 350 does not extendover the top wall 332. In addition, while in the fully engaged position,the distal end 332 of the first flange member 330 is positioned adjacentto and engaged against an outer side wall 346 of the second flangemember 334 and an outer side wall 347 of the third flange member 350,and the distal end 336 of the second flange member 334 is positionedadjacent to and may be engage against the distal end 352 of the thirdflange member 350 at a location along the first flange member 330.

The first flange member 330 has a length greater than the second flangemember 334 so that when the electrode cuff 310 is in the fully engagedposition, the first, second and third flange members 330, 334 and 350form a lumen 340 for receiving a nerve therein, with an inner side wall341 of the second flange member 134 and an inner side wall 354 of thethird flange member 350 forming an inner wall 342 of the lumen 340 so asto position the electrodes 112 (shown in FIG. 2), which are embeddedwithin the second flange member 334, adjacent to the nerve (not shown inFIG. 3). In addition, when the electrode cuff 310 is in the fullyengaged position, an inner side wall 344 of the first flange member 330is positioned over the outer side wall 346 of the second flange member334 and the outer side wall 347 of the third flange member 350, and anouter wall 348 of the first flange member 330 forms an outer wall 343 ofthe lumen 340. In this way, when the electrode cuff 310 is in the fullyengaged position shown in FIG. 10, both the first flange member 330 andthe second flange member 334 extend over the base portion 320, the firstflange member 330 forms an outer portion of the electrode cuff 310, andthe second and third flange members 334 and 350 form an inner portion ofthe electrode cuff 310 for engaging the nerve. Depending on the size ofthe nerve, once positioned about the nerve, the electrode cuff 310 maybe either in the fully engaged position of FIG. 10 or in a partiallyfully engaged position, wherein the distal end 332 of the first flangemember 330 may be positioned along the outer side wall 346 of the secondflange member 334 to be spaced further away from the second side wall328 than shown in FIG. 10, and the distal end 336 of the second flangemember 334 may be spaced further away from and not engaged against thedistal end 352 of the third flange member 350, as will be describedbelow.

FIG. 11 is a front view of the expandable cuff of FIG. 10 in anintermediate open position according to an embodiment of the invention.As illustrated in FIG. 11, during positioning of the electrode cuff 310over the desired nerve so that the nerve can be properly located withinthe lumen 340, the electrode cuff 310 is advanced from the fully engagedposition shown in FIG. 10, to an intermediate position shown in FIG. 11in which the distal end 332 of the first flange member 330 is advancedaway from the second side wall 328, and the first flange member 330 isadvanced away from the second flange member 334 so that the distal end332 extends outward in an opposite direction from the first side wall326 of the base portion 320. As a result, when the electrode cuff 310 isin the intermediate open position, the first flange member 330 is notpositioned so as to extend over the top wall 322 of the base portion320, while the second flange member 334 remains positioned to extendover the top wall 322 of the base portion 320, with the distal end 336adjacent to the distal end 352 of the third flange member 350. Inaddition, the inner side wall 344 of the first flange member 330 is nolonger positioned over and adjacent to the outer side wall 346 of thesecond flange member 334 when the cuff 310 is in the intermediate openposition of FIG. 11.

FIG. 12 is a front view of the expandable electrode cuff of FIG. 10 in afully open position according to an embodiment of the invention. Asillustrated in FIG. 12, once the electrode cuff 310 is in theintermediate open position, the distal end 336 of the second flangemember 334 is advanced away from the distal end 352 of the third flangemember 350 and the second flange member 334 is advanced to no longerextend over the top wall 322 of the base portion 320 and the first sidewall 326 so that the distal end 336 extends outward in the oppositedirection from the second side wall 328, resulting in the inner wall 342of the second flange member 334 no longer forming the lumen 340 when theelectrode cuff 310 is in the fully open position of FIG. 12. As aresult, when the electrode cuff 310 is in the fully open position,neither the first flange member 330 nor the second flange member 334 arepositioned so as to extend over or near the top wall 322 of the baseportion 320 of the electrode cuff 310, the inner side wall 344 of thefirst flange member 330 is no longer positioned over or near the outerside wall 346 of the second flange member 334, and the inner side wall341 of the second flange member 334 no longer forms the inner wall 342of the lumen 340.

In this way, by enabling the electrode cuff 310 to be advanced betweenthe fully engaged position, the intermediate open position, and thefully open position, the electrode cuff 310 can be more easilypositioned over a nerve during implantation of the lead 100, using thesame method of implantation as described above in FIG. 6, for example.If desired, an adhesive material (not shown) could be added to thedistal end 352 of the third flange member 350 in order to make asmoother transition at the distal end 352 and the inner wall 334 of thefirst flange member 330 during positioning of the electrode cuff 310about the nerve.

As can be seen in FIGS. 10-12, the second flange member 334 according toone embodiment has a first thickness 360 along a proximal end 362located at the top wall 322 of the base portion 120 along the secondside wall 328, and a second thickness, less than the first thickness360, at the distal end 336 of the second flange member 334, so that thesecond flange member 334 is tapered in thickness from the proximal end362 to the distal end 336. Similarly, the third flange member 350 has afirst thickness 364 along a proximal end 366 located at the top wall 322of the base portion 320 along the first side wall 326, and a secondthickness, less than the first thickness 364, at the distal end 352 ofthe third flange member 350, so that the third flange member 350 istapered in thickness from the proximal end 366 to the distal end 352.While the inner flange member 334 of FIGS. 8-10 is shown to be tapered,it is understood that both the inner flange member 334 and the outerflange member 332 could be formed without being tapered. In addition, itis understood that the inner flange member 134 of FIGS. 3-5 may also betapered as described in the embodiment of FIGS. 10-12.

The flange members described above may be formed from polyurethane,silicon or a blend of polyurethane and silicon. Furthermore, accordingto an embodiment, one of the flange members could be formed ofpolyurethane while the other is formed of silicon. If formed fromsilicone, then the durometer of the flange material range would bewithin a range of approximately 40 A-70 A. The thickness of the flangematerial could be from approximately 0.005 inches to 0.025 inches.Nominally, if the flange is formed of a polyurethane having a durometerof approximately 85 A, the flange would be 0.0075 inches thick. In theembodiment of FIGS. 10-12, the inner flange 334 is formed from moldedpolyurethane and the outer flange 330 is formed from a portion of apolyurethane tubing. In either embodiment, the polyurethane is formed tohave a “memory” that enables the flange members to be biased towards thefully engaged positioned. The lumen 140, 340 may have an inner diameterbetween 0.050 and 0.400 inches, while according to an embodiment, theinner diameter is approximately 0.140 inches in the fully engagedposition.

If the inner flange member 134, 334 is tapered, the respective proximalend 135 and 360 may have a thickness of approximately 0.025 to 0.030inches, and the distal end 136, 336 may have a thickness ofapproximately 0.001 to 0.010 inches. This provides a strong mechanicalconnection to the sidewall and also provides the needed thickness tohold and strain relief the electrodes. According to one embodiment, thedistal end 136, 336 has a thickness of 0.005 inches. Similarly, thedistal end 352 of the third flange member 350 may have a thickness ofapproximately 0.001 to 0.010 inches, and according to an embodiment inwhich the distal end 336 of the second flange member 334, the distal end352 of the third flange member would also have a thickness ofapproximately 0.005 inches.

FIG. 13 is a front view of an expandable electrode cuff positioned abouta nerve in an intermediate open position according to an embodiment. Asillustrated in FIG. 13, depending upon the circumference of the nerve200, once the nerve 200 is positioned over the top wall 322 of the baseportion 320 of the electrode cuff 310 and adjacent to the third flangemember 350, and the second flange member 334 is positioned about thenerve 200 during the advancement of the electrode cuff 310 from thefully open position of FIG. 10 to the intermediate open position, thedistal end 336 of the second flange member 334 may be positioned to bespaced further above the proximal end 331 of the first flange member 330and the distal end 352 of the third flange member 350 than when theelectrode cuff 310 is in the intermediate open position of FIG. 11. As aresult, the size of the lumen 340 can be increased relative to when theelectrode cuff 310 is in the intermediate open position of FIG. 11 toaccommodate the size of the nerve 200 during positioning of theelectrode cuff 310.

FIG. 14 is a front view of an expandable electrode cuff positioned abouta nerve in a fully engaged position according to an embodiment.Similarly, during the advancement of the electrode cuff 310 from theintermediate open position of FIG. 13 to the fully engaged positionduring implant of the electrode cuff 310, the distal end 332 of theouter flange member 330 may be positioned along the outer side wall 346of the second flange member 334 to be spaced further away from thesecond side wall 328 than when the electrode cuff 310 is in the fullyengaged position of FIG. 10, and to be above, rather than below the topwall 332 of the base portion 320. As a result, the diameter of the lumen340 is increased relative to when the electrode cuff 310 is in the fullyengaged position of FIG. 10 prior to being implanted, to accommodate thesize of the nerve. Therefore, as illustrated in FIGS. 13 and 14, inorder to accommodate the size of the nerve, the first and second flanges330 and 334 can be advanced or expanded to increase the diameter of thelumen 340.

FIG. 15 is a front view of an expandable electrode cuff positionedaround a nerve according to an embodiment of the invention. Asillustrated in FIG. 15, according to one embodiment, in order to addressthe effects of swelling of the hypoglossal nerve 200 that may sometimesoccur, particularly after the initial trauma associated with implantingthe electrode cuff 310, the first and second flange members 330 and 334are expandable so that the circumference of the lumen 340 formed by theelectrode cuff 310 can be increased to accommodate increases in thediameter of the nerve 200 that occur subsequent to the initialpositioning of the expandable electrode cuff 310 about the nerve 200, asillustrated in FIG. 14. For example, during swelling of the nerve 200subsequent to implant of the device 100, the first flange member 330 andthe second flange member 334 expand so that the distal end 332 of thefirst flange member 330 becomes positioned to be spaced further awayfrom the second side wall 328 of the base portion 320, and to be evenfurther above, rather than below, the top wall 322 of the base portion320 than when the electrode cuff 310 was initially positioned about thenerve to the position illustrated in FIG. 14. At the same time, thedistal end 336 of the second flange member 334 becomes positioned to bespaced further above the distal end 352 of the third flange member 350,and further away from the first side wall 326 and the top wall 322 ofthe base portion 320, thereby further increasing the size of the lumen340 to accommodate the swelling. As the swelling of the nerve 200subsides, the first and second flange members 330 and 334 return towardsthe original fully engaged position about the nerve 200 that occurredduring positioning of the electrode cuff 310 at the time of implant ofthe device, such as is illustrated in FIG. 14.

By forming the first and second flange members, described above, toextend over the base member so that each of the flange members extendfrom a proximal end located on one side of the base member to a distalend located along the other side of the base member, the electrode cuffwill continue to be positioned completely around the nerve, therebypreventing open gaps from being formed between the distal ends of theflange members as the nerve swells. Rather, the first and second flangemembers described above enable the necessary expansion of the flangemembers to accommodate increasing the diameter of the lumen required formaintaining the nerve to be completely enclosed within the lumen. Inthis way, using the electrode cuff described above, the opportunity forthe nerve to extend and extend out of the lumen is decreased, since theelectrode cuff is able to more effectively accommodate such swelling.

FIG. 16 is a top view of an expandable electrode cuff according to anembodiment of the invention in the fully open position. As illustratedin FIG. 16, according to an embodiment, an expandable electrode cuff 410includes a first flange member 430 and a second flange member 434extending from a base portion 420, as described above. Ends 432 and 436of one or both of the first flange member 430 and the second flangemember 434, respectively, may include having chamfered corners 435 toprevent the corners 435 from curling during placement of the expandableelectrode cuff 410 over the nerve, as described above.

FIG. 17 is a top view of an expandable electrode cuff according to anembodiment of the invention in the fully open position. As illustratedin FIG. 17, according to an embodiment, an expandable electrode cuff 510includes a first flange member 530 and a second flange member 534extending from a base portion 520, as described above. Ends 532 and 536of one or both of the first flange member 530 and the second flangemember 534, respectively, may include a suture 537 attached thereto. Forexample, one or more holes 539 may be formed along the ends or at therespective corners 535 for attaching a suture 537 to the flange member.The suture 537 is utilized to pull one or both of the flange members 530and 534 through and under the nerve during positioning of the electrodecuff 510 about the nerve while in the fully open position. In addition,the sutures 537 may also be utilized to aid in advancing the electrodecuff from the fully engaged position to the fully open position prior toplacement of the electrode cuff 510. Once the expandable electrode cuff510 is positioned under the nerve, the implanter merely releases thehold on the sutures 537 to allow either of the flange members 530 and534 to be engaged around the nerve, as described above, and the sutures537 may then be removed by being cut off from the electrode cuff 510.

According to an embodiment, the sutures 537 may come already attached tothe electrode cuff, or the electrode cuff may only include the holesformed at one or more of the ends, so that the implanter merely insertsthe sutures in the desired holes prior to positioning of the electrodecuff about the nerve.

FIG. 18 is a top view of an expandable electrode cuff according to anembodiment of the invention in the fully open position. As illustratedin FIG. 18, according to an embodiment, an expandable electrode cuff 610includes a first flange member 630 and a second flange member 634extending from a base portion 620, as described above. One or bothcorners of ends 632 and 636 of one or both of the first flange member630 and the second flange member 634, respectively, may include a moldedor attached tab 645, that, similar to the sutures of FIG. 17, areutilized pull one or both of the flange members 630 and 634 through andunder the nerve during positioning of the electrode cuff 610 about thenerve while in the fully open position. In addition, the tabs 645 mayalso be utilized to aid is advancing the electrode cuff 610 from thefully engaged position to the fully open position prior to placement ofthe electrode cuff 610. Once the expandable electrode cuff 610 ispositioned under the nerve, the implanter merely releases the hold onthe tabs 645 to allow either of the flange members 630 and 634 to beengaged around the nerve, as described above. In addition, an embodimentmay include a combination of the tabs 645 and one or more holes 639formed at the respective corners 635 of the ends 632 and 636 to aid inplacement of the electrode cuff about the nerve. If the use of suturesto aid in implant is desired, the implanter may merely inserts a suturein the desired hole 639.

FIGS. 19-21 are front views of an expandable electrode cuff according toembodiments of the invention. As illustrated in FIGS. 19-21, otherconfigurations of the flange members may also be utilized. An electrodecuff 410 according to one embodiment may include a second flange member434 and a third flange member 450 formed to have any desired lengths toenable the respective ends 436 and 452 to be positioned at any desiredlocation within the lumen 440. For example, as illustrated in FIG. 19,the distal end 436 of the second flange member 434 and the distal end452 of the third flange member 450 may be positioned further above thefirst side wall 426 than in the exemplary illustration of FIG. 10. Inaddition, in another embodiment the length of the first flange member430 may be increased so that the first flange member 430 extends overthe top wall 422 of the base portion 420, around the second flangemember 434 and under the bottom wall 424 of the base member 420, withthe distal end 432 of the first flange member 430 being positioned belowthe proximal end 431 of the first flange member 430 along the first sidewall 426.

As illustrated in FIG. 20, according to another embodiment, the lengthof a first flange member 530 may be even further increased so that thefirst flange member 530 extends over the top wall 522 of the baseportion 520, around the second flange member 534, under the bottom wall524 of the base member 520 and over the first flange member 530 alongthe proximal end 531 of the first flange member 530, with the distal end532 of the first flange member 530 being positioned above the proximalend 531 of the first flange member 530 along the first side wall 426.

As illustrated in FIG. 21, according to yet another embodiment, thesecond flange member 634 and the third flange member 650 may be formedto be symmetrical, with the distal end 636 of the second flange member634 positioned approximately the same distance above the second sidewall 628 of the base portion 620 as the distal end 652 of the thirdflange member 650 is positioned above the first side wall 626 of thebase portion 620. In addition, the length of the first flange member 630may be increased so that the first flange member 630 extends over thetop wall 622 of the base portion 620 a multiple number of times, aroundthe second flange member 434 and under the bottom wall 424 of the basemember 420 the multiple number of times, with the distal end 432 of thefirst flange member 430 being positioned at any location around theelectrode cuff 610, such as above the proximal end 431 of the firstflange member 430 along the first side wall 426, as shown in FIG. 21.

While at least one exemplary embodiment has been presented in theforegoing detailed description, it should be appreciated that variationsexist. It should also be appreciated that the exemplary embodiment orexemplary embodiments are only examples, and are not intended to limitthe scope, applicability, or configuration of the invention in any way.Rather, the foregoing detailed description will provide those skilled inthe art with a convenient road map for implementing the exemplaryembodiment or exemplary embodiments. It should be understood thatvarious changes can be made in the function and arrangement of elementswithout departing from the scope of the invention as set forth in theappended claims and the legal equivalents thereof

What is claimed is:
 1. An electrode cuff, comprising: a base memberincluding a first side wall, a second side wall, a top wall and a bottomwall; a first flange member including a proximal end and a first distalend; a second flange member including a second distal end and a proximalend extending from the second side wall, wherein the second flangemember is tapered from the proximal end to the second distal end; and athird flange member including a third distal end and a proximal endextending from the first side wall, wherein the third flange member istapered from the proximal end to the third distal end and the thirdflange member has a cross-sectional length substantially less than across-sectional length of the second flange member, wherein the thirddistal end is positioned above the first side wall of the base memberwithout extending over the top wall of the base member, wherein both therespective first and third flange members are biased to extend in afirst radial direction, wherein the second flange member is biased toextend in a second radial direction, opposite the first radialdirection, and wherein the first flange member overlaps both the secondand third flange members such that the third flange member, the secondflange member, and the first flange member generally provide avariable-sized lumen about a nerve, wherein a portion of the basemember, including a portion of the respective first and second sidewalls, extends generally outward and away from a proximal end of thethird flange member and from a proximal end of the second flange,respectively.
 2. The electrode cuff of claim 1, wherein the proximal endof the second flange member has a first thickness substantially greaterthan a second thickness of the second distal end of the second flangemember, and the proximal end of the third flange member having a firstthickness substantially greater than a second thickness of the thirddistal end of the third flange member.
 3. The electrode cuff of claim 2,wherein the third flange member, the second flange member, and the basemember are formed as a single unitary molded piece.
 4. The electrodecuff of claim 1, wherein the proximal end of the first flange member isattached against a proximal portion of the third flange member, andwherein a cross-sectional length of the first flange member issubstantially greater than the cross-sectional length of the thirdflange member.
 5. The electrode cuff of claim 1, the first side wall isspaced apart from and generally opposite the second side wall, and thebottom wall extends from the first side wall to the second side wall,and the top wall is spaced apart and generally opposite from the bottomwall.
 6. The expandable electrode cuff of claim 1, and furthercomprising an implantable stimulation system comprising: an implantablepulse generator; a stimulation lead having a lead body extending from alead body proximal end to a lead body distal end; and a connectorpositioned at the lead body proximal end for electrically connecting thestimulation lead and the implantable pulse generator, wherein theexpandable electrode cuff is positioned at, and supported by, the leadbody distal end.
 7. The expandable electrode cuff of claim 1, whereinthe second flange member is biased to extend in the second radialdirection over the top wall of the base member to cause the seconddistal end to be spaced above, and in releasable contact with, the thirddistal end at a point located laterally outward relative to the firstside wall of the base member.
 8. An expandable electrode cuff of animplantable stimulation system, comprising: a base member including afirst side wall, a second side wall, a top wall and a bottom wall; afirst flange member including a proximal end and a first distal end; asecond flange member including a second distal end and a proximal endextending from the second side wall, wherein the second flange member istapered from the proximal end to the second distal end with the proximalend of the second flange member having a first thickness substantiallygreater than a second thickness of the second distal end of the secondflange member; and a third flange member including a third distal endand a proximal end extending from the first side wall, wherein the thirdflange member is tapered from the proximal end to the third distal endwith the proximal end of the third flange member having a firstthickness substantially greater than a second thickness of the thirddistal end of the third flange member, and wherein the proximal end ofthe first flange member is attached to a proximal portion of the thirdflange member, wherein both the respective first and third flangemembers are biased to extend in a first radial direction, wherein thesecond flange member is biased to extend in a second radial direction,opposite the first radial direction, and wherein the first flange memberoverlaps both the second and third flange members such that the thirdflange member, the second flange member, and the first flange membergenerally maintain a variable-sized lumen to accommodate a changing sizeof a nerve.
 9. The electrode cuff of claim 8, wherein the third flangemember is biased to position the third distal end above the first sidewall of the base member without extending over the top wall of the basemember.
 10. The electrode cuff of claim 9, wherein the first flangemember is biased to extend in the first radial direction over both thetop wall of the base member and the second flange member, and the secondflange member is biased to extend in the second radial direction overthe top wall of the base member to cause the second distal end to bespaced above, and in releasable contact with, the third distal end at apoint located laterally outward relative to the first side wall of thebase member.
 11. The electrode cuff of claim 10, wherein across-sectional length of each respective first and second flange memberis substantially greater than a cross-sectional length of the thirdflange member.
 12. The electrode cuff of claim 11, wherein the length ofthe first flange member is configured to position the first flangemember to overlap substantially the entire length of the second flangemember.
 13. The electrode cuff of claim 8, wherein a portion of the basemember, including a portion of the respective first and second sidewalls, extends generally outward and away from a proximal end of thethird flange member and from a proximal end of the second flange,respectively.
 14. The electrode cuff of claim 13, the first side wall isspaced apart from and generally opposite the second side wall, and thebottom wall extends from the first side wall to the second side wall,and the top wall is spaced apart and generally opposite from the bottomwall.
 15. The electrode cuff of claim 8, wherein the third flangemember, the second flange member, and the base member are formed as asingle unitary molded piece.
 16. The electrode cuff of claim 8, andfurther comprising an implantable stimulation system comprising: animplantable pulse generator; a stimulation lead having a lead bodyextending from a lead body proximal end to a lead body distal end; and aconnector positioned at the lead body proximal end for electricallyconnecting the stimulation lead and the implantable pulse generator,wherein the expandable electrode cuff is positioned at, and supportedby, the lead body distal end.
 17. An electrode cuff comprising: a basemember including a first side wall, a second side wall, a top wall and abottom wall; a first flange member including a proximal end and a firstdistal end; a second flange member including a second distal end and aproximal end extending from the second side wall, wherein the secondflange member is tapered from the proximal end to the second distal end;and a third flange member including a third distal end and a proximalend extending from the first side wall, wherein the third flange memberis tapered from the proximal end to the third distal end and the thirdflange member has a cross-sectional length substantially less than across-sectional length of the second flange member, wherein the thirddistal end is positioned above the first side wall of the base memberwithout extending over the top wall of the base member, wherein both therespective first and third flange members are biased to extend in afirst radial direction, wherein the second flange member is biased toextend in a second radial direction, opposite the first radialdirection, and wherein the first flange member overlaps both the secondand third flange members such that the third flange member, the secondflange member, and the first flange member generally provide avariable-sized lumen about a nerve, wherein the proximal end of thefirst flange member is attached against a proximal portion of the thirdflange member, and wherein a cross-sectional length of the first flangemember is substantially greater than the cross-sectional length of thethird flange member, and wherein a portion of the base member, includinga portion of the respective first and second side walls, extendsgenerally outward and away from a proximal end of the third flangemember and from a proximal end of the second flange, respectively. 18.The electrode cuff of claim 17, wherein the third flange member, thesecond flange member, and the base member are formed as a single unitarymolded piece.
 19. The electrode cuff of claim 18, the first side wall isspaced apart from and generally opposite the second side wall, and thebottom wall extends from the first side wall to the second side wall,and the top wall is spaced apart and generally opposite from the bottomwall.
 20. The electrode cuff of claim 18, wherein the proximal end ofthe second flange member has a first thickness substantially greaterthan a second thickness of the second distal end of the second flangemember, and the proximal end of the third flange member having a firstthickness substantially greater than a second thickness of the thirddistal end of the third flange member